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Subject[ 37/99] cpufreq / intel_pstate: Change to scale off of max P-state
Date
3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dirk Brandewie <dirk.j.brandewie@intel.com>

commit 2134ed4d614349b2b4e8d7bb593baa9179b8dd1e upstream.

Change to using max P-state instead of max turbo P-state. This
change resolves two issues.

On a quiet system intel_pstate can fail to respond to a load change.

On CPU SKUs that have a limited number of P-states and no turbo range
intel_pstate fails to select the highest available P-state.

This change is suitable for stable v3.9+

References: https://bugzilla.kernel.org/show_bug.cgi?id=59481
Reported-and-tested-by: Arjan van de Ven <arjan@linux.intel.com>
Reported-and-tested-by: dsmythies@telus.net
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/cpufreq/intel_pstate.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -103,10 +103,10 @@ struct pstate_adjust_policy {
static struct pstate_adjust_policy default_policy = {
.sample_rate_ms = 10,
.deadband = 0,
- .setpoint = 109,
- .p_gain_pct = 17,
+ .setpoint = 97,
+ .p_gain_pct = 20,
.d_gain_pct = 0,
- .i_gain_pct = 4,
+ .i_gain_pct = 0,
};

struct perf_limits {
@@ -468,12 +468,12 @@ static inline void intel_pstate_set_samp
static inline int intel_pstate_get_scaled_busy(struct cpudata *cpu)
{
int32_t busy_scaled;
- int32_t core_busy, turbo_pstate, current_pstate;
+ int32_t core_busy, max_pstate, current_pstate;

core_busy = int_tofp(cpu->samples[cpu->sample_ptr].core_pct_busy);
- turbo_pstate = int_tofp(cpu->pstate.turbo_pstate);
+ max_pstate = int_tofp(cpu->pstate.max_pstate);
current_pstate = int_tofp(cpu->pstate.current_pstate);
- busy_scaled = mul_fp(core_busy, div_fp(turbo_pstate, current_pstate));
+ busy_scaled = mul_fp(core_busy, div_fp(max_pstate, current_pstate));

return fp_toint(busy_scaled);
}



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